With the development of human civilization from industrial civilization to ecological civilization, human beings have increasingly strengthened their protection of the global environment. The development and utilization of renewable, low-emission and even zero emission eco-friendly power methods have been highly valued and sustained.
In the early days of industrial civilization, it was the era of steam engine. In the 19th century, due to the utilization of energy and the demand for power efficiency, the steam engine developed to the extreme was permanently replaced by the internal combustion engine, and the second power revolution occurred. Up to now, the internal combustion engine is also a mainstream power method highly industrialized with highly improved energy efficiency utilization, and has made an epoch-making contribution to the development of human industrial civilization.
However, both steam engine and internal combustion engine naturally have problems such as low energy efficiency and large emissions of environmentally unfriendly substances.